When trying to figure out the cause of your symptoms, your doctor will ask for samples of your blood and bone marrow. These samples will be used in a number of tests.

About Blood Tests

The tests on your blood help your doctor find out what type of MDS you have. Some of the results can be confusing. This section explains your blood test results. Compare this section with the results of your blood work. It can help you better understand the lab report.

One important test is a complete blood count or CBC for short. The CBC measures the number of each blood cell type in your blood sample. If the CBC shows a low number of red blood cells, white blood cells, or platelets, your doctor may look at the cells under a microscope. This is called a blood smear, and it shows whether any red blood cells are not normal.

Your doctor will ask you to get a CBC, and possibly other blood tests, on a regular basis. This will allow your doctor to know if your blood counts are high or low and if they have changed from the last time you had a CBC. If your blood counts are abnormal or have changed, your doctor may try to find out why.

The Risk of Getting AML (Acute Myelogenous Leukemia)

AML is a cancer of the white blood cells. It is defined as having more than 20 out of every 100 white blood cells in the bone marrow which are immature white blood cells called blasts.

In people with AML, blasts make copies of themselves quickly. This slows the production of red blood cells, which causes a low red count (anemia). It also slows the production of platelets, which leads to a greater risk of serious bleeding.

Over time, some cases of MDS become AML. But most do not. Your risk of developing AML depends largely on which MDS subtype you have. The following subtypes are more likely to become AML:

* If you have RA (Refractory Anemia) or RARS (Refractory Anemia with Ringed Sideroblasts), you have a 1 in 10 to 2 in 10 chance of developing AML.* If you have RAEB-1 (Refractory Anemia with Excess Blasts) or RAEB-2, you have a greater than 4 in 10 chance of developing AML.

Other blood tests

Your doctor may order other blood tests after getting results from your CBC.

EPO level

EPO, or erythropoietin, is a protein made by your kidneys. It is created in response to low oxygen levels in the body - in other words, in response to anemia. EPO causes your bone marrow to make more red blood cells. A shortage of EPO can also cause anemia. A low EPO level may be a sign of a problem other than MDS, or it may make anemia worse in people who have MDS.

Iron level

If you have anemia, your doctor may also check the level of iron in your blood. A shortage of iron can cause anemia.

If your red blood cells have an abnormal shape, size, or look, your doctor will check the levels of vitamin B12 and folate in your blood. A shortage of these vitamins can cause dysplasia, or cells that are not normal, and this can lead to anemia.

About Bone Marrow Tests

Bone marrow tests are done for several reasons. Most likely, your doctor examined your bone marrow to confirm you have MDS. The doctor may also do a bone marrow exam now and again to find out if your MDS has stayed the same, improved, or worsened since the last exam.

The bone marrow test shows:

Exactly what types and amounts of cells your marrow is making

Levels of bone marrow blasts (immature white blood cells); if more than 5 out of every 100 white blood cells in your bone marrow is a blast cell, this is not normal

Damaged chromosomes (DNA) in the cells of your bone marrow. These are called cytogenetic (sie-toe-juh-NEH-tik) abnormalities. Some chromosome abnormalities are linked to specific MDS sub-types

When speaking about MDS, blasts are very young white blood cells. In normal bone marrow, no more than 5 out of 100 white cells are blasts. But people with MDS may have too many blasts in their bone marrow.

The number of blasts in the bone marrow is used to define how severe your MDS is:

If less than 5 out of 100 white cells in your bone marrow are blasts, you have lower-risk MDS.

If between 5 out of 100 and 19 out of 100 white cells in your bone marrow are blasts, you have higher-risk MDS.

If 20 or more out of 100 white cells in your bone marrow are blasts, you have AML or acute myelogenous leukemia. About 30 out of 100 patients diagnosed with MDS will eventually have AML.

Originally published on 03/03/2011 - 5:02pm. Last updated on Tue, 01/20/2015 - 4:42pm.